package interview;

import java.util.Scanner;

public class zuiyou02 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] dp = new int[n + 1];
        if (n == 1){
            System.out.println(1);
            return;
        }
        if (n == 2){
            System.out.println(2);
            return;
        }
        dp[0] = 1;
        dp[1] = 1;
        for (int i = 2; i <= n; i++){
            for (int j = 1; j <= i; j++){
                dp[i] += dp[j - 1] * dp[i - j];
            }
        }
        System.out.println(dp[n]);
    }
}
